Urethra of Animals
Urethra of Animals is a long mucous tube extending from the neck of the bladder to the tip of glans penis.
Urethra of Bull
Urethra of Bull passes backwards on the floor of the pelvis, turns around the ischial arch forming a sharp bend and then passes forward to be included in the body of the penis. It has therefore pelvic and extra pelvic or penile parts. The pelvic part is 12 cm long and is relatively small and uniform in diameter. The urethral muscle encloses it ventrally and laterally and is very thick. It is related to the rectum and prostate above, the obturator muscles below and the Cowper’s gland laterally. The extra pelvic or penile part passes between the two crura of the penis turns forward and is included in the body of the penis.
Here the corpus spongiosum and bulbo-cavernous muscle covers it. The tube forms an enlargement at its beginning, the bulbus urethrae. It then gradually diminishes in diameter and very small at its termination, forming processus urethrae.
The opening from the bladder into the urethra is termed internal urethral orifice, it is closed except during urination. The terminal opening is known as external urethral orifice.
The colliculus seminalis is a rounded prominence, situated medially on the dorsal wall about 5 cm behind the internal urethral orifice and on it are two slit-like openings situated close together.
These are the ejaculatory orifices at which the vas deferens and the excretory duct of seminal vesicle open
The urethral crest is a median ridge of mucous membrane in the dorsal wall of the urethra
The crest extends forward from the colliculus, while two mucous folds pass backward from the colliculus.
A little lateral and caudal to the colliculus are the openings of the prostate and behind are the ducts of the Cowper’s gland.
Urethra of Ram and Buck
The urethra lies in a groove on the ventral surface of the corpus cavernosum in Ram and Buck.
Its terminal part projects commonly about an inch and half beyond the glans penis, forming twisted processus urethrae.
Urethra of Stallion
Pelvic part is 10 to 12 cm long and 5 to 6 cm in diameter in stallion. The extra pelvic part is 1.5 cm in diameter.
The colliculus seminalis presents on either side a small diverticulum in which the vas deferens and the duct of seminal vesicle opens.
Lateral to this are the openings of the prostatic ducts and further back are openings of the ducts of the Cowper’s gland.
Urethra of Boar
Urethra of Boar has a very long pelvic part and covered by a thick urethral muscle except dorsally where there is a dense fibrous layer.
Urethra of Dog
The bulb of the urethra is well developed in case of Dog.
Urethra of Rabbit
The external urethral orifice is placed dorsally and little cranially in Rabbit.
Urethra of Cock
Urethra is absent in cock.
